Portable crane



June 1, 1937.

G. A. M CLAIN PORTABLE CRANE Filed May 18, 1935 5 Sheets-Sheet 2 l 30422 *ysz INVENTOR. 6R0 VER A Mc CLA/N A T'I'ORNE YS.

June 1, 1937. A, MocLAlN 2,082,017

PORTABLE CRANE Filed May 18, 1935 5 Sheets-Shut 3 f9 84 T"). E J 88 87%82 5 INVENTOR. I

GROVER A, McCLA/N ATTORNEYS June 1, 1937.

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10/ 100 .91 .99 1 l' L xex x \m \2\ \a W W W "I' V G. A. M CLAINPORTABLE CRAP.

Filed May 18, 1935 5 Sheets-Sheet 4 INVENTOR. GROVER AQMCCLA/N BY MATTORNEYS G A. MCCLAIN 2,082,017

PORTABLE CRANE Filed May 18, 1935 5 Sheets-Sheet 5 INVENTOR. GROVE? A.Mc CLA/N y 1 @01 1 ATTORNEYS.

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June 1, 1937.

Patented June 1,1937

UNITED STATES PORTABLE CRANE v Grover A. McClain, San Francisco, Calif.,as-

signor of one-tenth Alameda, Calif.,

to James Harry Layne,

one-tenth to Harold L.

McClain, and one-tenth to Romey McClain, both of San Francisco, Calif.

Application May 18,

6 Claims.

My invention relates to improvements in portable cranes, and it consistof the combinations, constructions and arrangements hereinafterdescribed and claimed.

An object of my invention is to provide a crane which is designed to beplaced on the standard truck, the crane being so mounted on the truck asto give space on the truck body to carry and transport articles liftedby the crane. In standard truck cranes the chassis must be reinforced toa considerable extent in order to support the additional load of thecrane, and to further support the work when it is lifted by the crane.Another feature of my invention is the provision of a caster wheelmounted directly below the mast of the crane, this wheel being broughtinto'play when the crane is used for lifting loads, the wheel acting asa direct support between the mast and the ground or other supportingsurface.

In this way the load upon the crane when lifting an object istransmitted directly to the ground through the caster Wheel rather thanto the truck chassis. The result is that a lighter truck chassis can beused for supporting the crane since the only weight needed in thechassis is that which is sufficient to support the crane when carryingno work. Of course the truck will still aid the caster wheel insupporting the load carried by the crane because the crane is carried bythe truck and caster wheel.

A further object of my invention is to provide a device of the typedescribed in which a stationary. mast is carried by the truck chassis,and is positioned so as to be out of the way of any load carried by thechassis, and in which the rtary mast is mounted on the upper part of thestationary mast, the rotary mast carrying the boom of the crane. Therotary mast can also carry the power source for the crane, or this powersource may be disposed at the bottom of the stationary mast, or may evenbe mounted adjacent to the truck engine, and operated thereby.

The device is so constructed that it may be lifted off the truckchassis, and the truck used for ordinary purposes. The stationary mastmay be mounted at'any desired position on the truck chassis eitherdirectly in back of the drivers seat as shown in one of the drawings, ormounted at the rear of the truck as shown in a simplified form of theinvention on another drawing.

Other objects and advantages will appear in the following specification,and the novel features of the device will be particularly pointed out inthe appended claims.

My invention is illustrated in the accompanying drawings forming a partof this application, in which Figure 1 is a side elevation of the deviceshown operatively applied to a truck chassis;

1935, Serial No. 22,273

Figure 2 is a plan view of a portion of the device shown in Figure 1;

Figure 3 is a sectional view taken substantially along the line 3-3 ofFigure 1;

Figure 4 is a transverse section through the lower portion of therotating mast;

Figure 5 is a vertical section through the top of the rotating mast;

Figure. 6 is a section along the line 6-6 of Figure 4;

Figure 7 is a sectional view of a part of the actuating mechanism;

Figure 8 is a side elevation of the caster wheel;

Figure 9 is a vertical section substantially along the line 9-9 ofFigure 8;

Figure 10 is a section along the line l0|ll of Figure 8;

Figure 11 is a section substantially along the line ll-II of Figure 8;

Figure 12 is a section along the line l2-|2 of Figure 10;

Figure 13 is a side elevation of a modified form of the invention;

Figure 14 is a top view of the rotating mast shown in Figure 13;

Figure 15 is a perspective view of a simplified form of stationary androtary masts; and

Figure 16 is a side elevation of the form oithe device shown in Figure15, portions being shown in elevation.

In carrying out my invention I make use of a is formed from two channelirons 1-1 that have their leg portions facing each other, and an I-beam.8 that is disposed between the channels l-l. A plate 9 extends along theunder side of the channels and I-beams, and is secured thereto and tothe truck chassis. A second plate l0 extends along the tops of thechannels 1 and I-beam 8, and is also secured thereto. At the place wherethe mast 5 joins the box beam 6 I dispose a heavier supporting plate H,and the mast 5 is secured to this plate and the plate in turn is securedto the elongated plate Hi. In this manner the mast 5 is supported by thebox beam 6 and by the truck chassis 2.

The mast 5 is additionally supported by a pair of rear angle irons l2,two pairs of side angle irons l3, and a pair of front angle irons I4,see Figure 1. A web of sheet metal i5 is secured to the pair of angleirons l2, and also to the mast 5 for providing additional support. Inlike mannor Figure 2 shows the pairs of side angle irons 13 as beingdisposed on opposite sides of webs 16 that extend from theangle irons tothe mast and to the box beam 6. Also the front pair of angle irons l4are disposed on opposite sides of a web 11 that placed between the angleirons and the mast 5. In this way the mast 5 is supported in a verticalposition.

The upper portion of the stationary mast 5 rotatably carries a rotatingmast l8. Figures 1, '4 and 5 show the construction of this rotating mastl8. It will be noted from these figures that the mast I8 is composed ofabottom casting I9, a tubular member threaded into the casting at 2 I.and a top casting 22 threaded into the top of the member 20 at 23. Themeans for rotatably supporting the casting 19 comprises a coneshapedportion 24, see Figure 4, which is welded or otherwise secured to thestationary mast at a point just above the angle irons I2, l3 and I4. Ataper roller bearing 25 is supported by the portion 24, and in turnrotatably supports the casting 19.

The top casting 22 rotates about the top of the stationary mast 5, and aroller bearing 26 is disposed between the casting 22 and the stationarymast 5. mast 5 as shown at 28, and this ring houses the top of theroller bearing 26 and acts as a retaining member for the top casting 22.In this simple way the mast I8 is rotatably mounted on the stationarymast 5.

The rotating mast l8 carries a boom 29 which is pivoted to the castingl9 at 30, see Figure 4.

The boom may be of any length desired and carries a pulley housing 3| atits outer end and also an extension 32.

The source of power for raising and lowering the boom and for rotatingthe mast l8, and also for moving the cables hereinafter described may bemounted on the rotating mast I8, if desired. This form is illustrated inFigures 1, 2, and 4.

A platform 33 is carried by the casting l9 and bracing 34 extends fromthe platform 33 to the top casting 22. Figures 1 and 2 show the platform33 as carrying a standard hoisting engine 35 and hoisting drums 36. Theengine 35 may be of any type desired, or it may be an electric motor orother source of power. One of the drums 36 has a light load line 31wrapped therearound, this line then being passed over a sheave 38carried by the side of the mast l8, and then over one of the upper setof pulleys 39 in the housing 3|, and finally over a pulley 40 on the bar32. A load hook 4|.is secured to the free end of the line or cable 31,and this cable is used for lifting light loads. This construction isstandard, and therefore needs no further description.

A heavy load line 42 leads from another drum 36 and is passed betweenpulleys 43 disposed on the side of the rotating mast I8. The load lineis then passed over another one of the upper set of pulleys 39, and thendown over another pulley constituting one of a lower set of pulleys 44.The cable is then passed around a block and tackle indicated generallyat 45, and then up over the other pulleys in the lower set 44 until asufficient number of turns has been made for lifting a heavy load. Thefree end of the load cable 42 may then be secured to the top of the mainload housing as shown at 46. A load hook 41 is raised and lowered bymeans of the cable 42.

The boomraising and lowering cable 48 extends from a third drum 36 andis passed around a sheave 49 on the side of the mast I8, and is then Aring 21 is recessed in the stationary passed around a sheave 50 on thecasting 22. The boom cable 48 then extends around one of the pulleys ofthe upper set 39 and back to a pulley 5|, see Figure 2, which isdisposed on the opposite side of the casting 22. The cable 48 is thenled to another one of the upper set of pulleys 39 and finally isdead-ended at a bracket 52 carried by the casting 22. It will be seenfrom this construction that the operator standing on the platform'33 canmanipulate the various drums 36 for actuating the light load line 42,the heavy load line 31 and the boom line 48. Clutches, not shown, andoperated by cranks 53are used for connecting any one of the drums 36desired to the power source.

The means for rotating the mast I8 is shown in Figures 1, 3, 4, 6 and'7. In Figure 4 I show a worm gear 54 composed of two parts and securedto the conical portion 24. A. worm 55, see Figure I 6, meshes with theworm gear 54, and in turn has a worm gear 56 operatively connectedthereto. Figure 7 shows the worm gear 56 in mesh with a second Worm 51which is splined at 58 to a hollow shaft 59. Figure 3 shows the shaft 59splined to a sleeve 60 which carries a beveled gear 6| at its inner end.The beveled gear 6| is mounted on a tubular portion 62 of a collar 63,which in turn is loosely mounted on a driven shaft 64. The ball racepermits the sleeve 60 to rotate about a supporting pin 66, which iscarried-by the collar 63. In this way a bearing support for the sleeve60 and the shaft 59 is done away with.

- The collar 63 is mounted between two bevel gears 61 and 68, and thesegears have clutches 69 and 19 that are keyed to the shaft 64. The shaft64 is rotated by a pinion 1| which is connected to the engine 35 by agearing indicated generally at 12 in Figure 2.

A rod 13 shown in Figure 3 carries forks 14 and 15 by means of which theclutches 69 and 10 operatively connect either the bevel gear 61 or thebevel gear 68 to the shaft 64. In'this way the shaft 59 is rotated ineither direction. In Figure 2 the rod 13 is shown connected to a lever16 which may be manually swung in either direction for effectingrotation of the shaft 59 in the desired direction.

It will be seen from this construction that the operator can rotate themast 18 in either direction desired, the mast carrying with it the boom29 and the source of power 35. In Figure 4 I show the two parts of theworm gear 54 connected to the cone-shaped member 24 by bolts 11 or othersuitable fastening means. In Figure '7 I show the particularconstruction of the housing which encloses the worm gear 56 and the worm51.

The housing is indicated at 18 and is rockably mounted on the shaft 19of the worm 55. The casting encloses the worm gear 56 with the exceptionof one face of the gear, and this face is closed by a cover plate whichis bolted or otherwise secured to the casting 18 by cap screws 81.

The top of the casting 18 is opened and carries projections 82 whichconstitute bearings for the shaft 83 of the worm 51. Thrust bearings 84are disposed between the worm 51 and the projections 82. The collars 85bear against the outer faces of the projections 82 and are secured inplace by pins 86. A removable cap 81 covers the top of the worm 51 andis secured to the projections 82 by screws 88, or other suitable fastening means. As already stated the shaft 83 is splined to the hollow shaft59 and is rotated thereby.

It will be seen from this construction that the hollow shaft 59 canswing freely about the shaft 64, see Figure 3, due to the collars 63.Also the housing I8 is free to rock about the shaft 19 and this willpermit any angular adjustment between the shafts I9 and 64 to be takenup by the hollow, shaft 59 and its associate mechanism.

When the crane is used for lifting a load from the side of a truck it isnecessary to counterbalance the weight of the boom 29. In Figures 1 and8 I show movable I-beams 89 disposed between the channels I and theI-beam 8. These I-beams 89 may be extended as shown in Figure 2 forcounter-balancing the weight of the boom 29. Also blocks, not shown, maybe disposed between the extended I-beams 89 and the ground forpreventing the overturning of the truck chassis when a heavy load isbeing liftedby the crane.

I also provide a caster wheel which is designed primarily to support themast through the box beam when the mast is being used for carrying aload. This caster wheel is shown generally in Figure 1, and is shown indetail in Figures 8 to 12 inclusive. Figure 8 shows the box beam 6 ascarrying triangularly shaped members 90. Two of these members aredisposed on each side of the box beam and they are welded to the beamand to a plate 9| that extends beneath the beam. The plate 9| is shownin Figure 10, and it will be noted that this plate hastriangularly-shaped openings 92 and 93. The apexes of these openingsface toward the box beam while the bases are arcuate in shape and aredisposed further away from the box beam.

A movable plate 94 is disposed beneath the plate 9| and is connectedthereto by bolts 95. These bolts have spacing sleeves 96 mounted thereonfor spacing the movable plate 94 a predetermined distance from a bar 91.This bar is merely for the purpose of spacing the bolts 95 the properdistance from each other. Sleeve rollers 98 are mounted on the spacers96 and bear against the edges of the triangularly-shaped openings 92 and93. A ball race 99 is disposed between the fixed plate 9| and themovable plate 94. This ball race is in the form of a disc with aplurality of openings I therein for receiving ball bearings IOI. Thediameter of the balls IOI is greater than the height of the disc 99, andtherefore a free moving connection between the moving plate 94 and thefixed plate 9| is provided.

As a means for holding the ball race 99 in the proper central position Isecure a rectangular frame I02, see Figure 10, to the fixed plate 9| byscrews or other suitable fastening means. Springs I03 extend from thecorners of the frame I02 to the disc 99 and tend to hold the disccentrally in the frame. The area of the frame I02 is large enough topermit the bolts 95 to move from one side of the triangular recesses 92and 93 to the opposite side without the disc contacting the inner wallof the frame. As

already stated the tendency of the springs will be to center the disc 99in the frame I02.

The moving plate 94 carries a caster wheel I04. Figure 9 shows dependingtriangularlyshaped plates I secured to the under surface of the plate94. The plates I 05 are disposed in two pairs and they provide guidewaysI09 therebetween, see Figure 11. The wheel I04 is'rotatably mounted on ashaft I01 and the square ends I08 of the shaft are mounted in blocks I09which ride between the guideways I 06. Figure 11 shows the blocks I09 ashaving recesses H0 for receiving the inner edges of the plates I05.

' Guide strips III are welded to the depending plates I05, and cooperatewith the guides I09 for guiding the blocks I09. Springs II2 are disposedbetween the plates III and bear upon the tops of the blocks I09. Fixedblocks 3 are disposed at the tops of the plates III and the tops of thesprings II2 bear. thereagainsh It will be seen from this constructionthat the springs II2 tend to move the sliding block I09 downwardly forcausing the caster wheel I04 to engage with the ground. The springs II2auto matically proportion the load, carried by the crane, between thevehicle I and the caster wheel I04.

When the caster wheel is used it is free to move longitudinally relativeto the truck chassis a slight distance and is also free to swing througha slight arc in accordance with the movements 3 of thetruck. Forexample, should the truck be moving forwardly the fixed plate 9| wouldhave a tendency to move to the right in Figure 10. The moving plate 94would remain stationary with respect to the ground until the bolts 95would have their rollers 98 contact respectively the apex of thetriangular recess 92 and the base of the triangular recess 93. The ballrace 99 would permit this movement and the springs I03 would allow thedisc 99 to move through half the distance taken by the bolts 95. If nowthe truck should be turned to the right or to the left, the front bolt95 would act as a pivot for the moving plate 94 and the rear bolt 95would swing in the recess 93 depending on the movement taken by thetruck. The swinging movement of the rear bolt 95 would permit the movingplate 94 to swing in the same manner, and to allow the caster wheel I 04to turn with the front wheels 3 of the truck. In this simple manner thewheel I04 is prevented from dragging over the ground. Should the truckbe moving in the reverse direction the parts would function in the samemanner, except that in this instance the rear bolt 95 would be disposedat the apex of the triangular slot 93, while .the front bolt 95 would bedisposed at the base of its triangular opening 92. If the operatorwishes to provide a non-yielding connection between the caster wheel I04and the truck chassis during the operation of the crane, a block, not

shown, may be disposed beneath the plate 94 and the under surface of theblock can rest directly on the top of the wheel I 04, or the block canbe made U-shaped and have its legs rest on the sliding blocks I09.

When the caster wheel is not in use it may be lifted from the ground bythe following mechanism: A pin I I4 is carried by the rear pair oftriangular pieces 90 and a pair of cables I I5 are connected to the endsof the pin 4 and these cables are passed around pulleys II6 mounted onthe shaft I01. The cables are then extended upwardly and have their endssecured to a shaft I I 1.

A crank handle 8 is mounted on the shaft, and this handle may be turnedfor rotating the shaft I I1 and winding the cables I I5 therearound.This will lift the sliding blocks I 09 and will free the caster wheelI04 from the ground. A pawl and ratchet mechanism H9 is used for lockingthe shaft II'I against rotation.

In Figures 13 and 14 I show a slightly modified form of mast. In thisform the power source for the boom and the load cables is not carried bythe rotating mast I0, but instead is disposed at the base of thestationary mast 5. I only show two drums I20 and I2I for actuating theboom cable line I22 and aload cable line I23. The light load line 31 isnot used in this form of the device.

The drums I20 and I2I may be actuated by any source of power either fromthe truck engine, not shown, or from a separate source. I haveillustrated in Figure 13 two worms I24 that rotate the drums I20 and I2Iin the manner desired by the operator. The worm I24 may be mounted on asingle shaft I25, and this shaft may in turn be operatively eonnected tothe truck engine through beveled gears I26 and a shaft I21.

I use the hollow mast 5 for conducting the cables I22 and I23 upwardlyto the top of the rotating mast I8. Pulleys I28 and I29 are disposed atthe bottom of the mast 5 and lead the cables I22 and I23 respectivelyinto the interior of the mast 5. Figure 14 shows two pulleys I30 andI3I, rotatably mounted between angle irons I32 which, in turn. arecarried by the top casting 22. The cable I22 is passed over the pulleyI30 and the cable I23 is passed over the pulley I3 I. The rotation ofthe drums I20 and I2I is controlled by the operator for raising andlowering the boom 29, and for raising and lowering the main load hook41, not shown, in Figures 13 and 14.

The rotating ma t I8 may be swung about the stationary mast 5 either bypower or by hand, and I have shown a worm I33 meshing with the worm gear54, and the worm is rotated by a hand crank I34 for swinging the mast I8on the mast 5. In all other respects this form of the device isidentical to the form already described, and therefore like referencenumerals will be applied and further description is unnecessary.

Another modified and simplified form of crane is shown in Figures 15 and16. In Figure 15 I illustrate a truck body at I35, and this body has astationary mast I36 mounted at any convenient place on the truck. Figure15 illustrates the mast I36 as being disposed at one of the rear cornersof the truck body. A collar I31 is secured to the stationary mast I36and a rotating mast I38 rides on the collar I31 and rotates about thestationary mast I36. A boom I39 is carried by the bottom of the rotatingmast I38 and is held in adjusted position by means of a link I40. Asheave or pulley MI is mounted at the free end of the boom I39, and aload line I42 is passed over this sheave and then over a second sheaveI43 carried by the top of the rotating mast I38. A drum I44 is mountedat the base of the stationary mast I36 and the load line I42 is wrappedtherearound. A crank I45 is used for paying out or winding in the loadline. The free end of the load line I52 carriesa load hook i-IB. Theline I42 is passed down through the hollow mast I36 and out over apulley M2 to the drum I44.

The operation of this form of the device is the same as that set forthin the other two forms except that the device is manually actuated. Theboom I39 is free to rotate about the mast I36 and can swing loads fromthe ground and convey them into the truck body. A pawl and ratchetindicated generally at I41 is used for supporting the load in anydesired position.

A keeper plate I06 is disposed at the bottom of each guideway I II andacts as a stop for lim ting the downward movement of the wheel I04 andaxle I01. Figure 9 shows a space between the plate 9 and the plate 9|for slidably receiving the bar 91. The bases of the lriangular recesses92 and 93 are arcuate in shape as already stated, and the radius of eacharc has its center in the apex of the opposite recess.

While I have shown only the preferred forms of my invention, it shouldbe understood that various changes or modifications may be made withinthe scope of the appended claims without departing from the spirit ofthe invention.

I claim:

The combination with a truck, of a stationary mast carried thereby, arotatable mast mounted at the top of the stationary mast, a boompivotally carried by the rotatable mast, and a caster wheel mountedbeneath the stationary mast and designed to rest on the ground toprovide a direct support for the stationary mast from the ground and toaid the truck in supporting the mast when the latter is carrying a load.1

2. The combination with a truck having a body, of a stationary mastcarried thereby, a second mast rotatable on the first, a boom carried bythe rotatable mast, a caster wheel for aiding the truck in supportingthe stationary mast when supporting a load, said wheel turning in thedirection in which the truck is moving for supporting the mast duringthe movement.

3. In combination, a truck frame, a crane supporting member carried bythe frame, a crane mounted on the supporting member, and a caster wheelmounted beneath the supporting member for aiding the frame in supportingthe crane when the latter carries a load, said mounting for the casterwheel comprising a member movable with respect to the crane supportingmember, frictionless means disposed between the members, and guide meansfor permitting either end of the caster wheel to swing laterally as thetruck frame is moved over the ground, this depending on the direction oftruck frame movement.

4. The combination with a truck provided with a drivers compartment, ofa crane mounted on the truck immediately in back of the compartment andcomprising a stationary mast secured to the truck, a rotatable mastdisposed on the upper end of the first mast and terminating just abovethe drivers compartment, a boom and a power unit carried by therotatable mast and extending diametrically away from each other, andmeans actuated by the power unit for rotating the rotatable mast, saidboom and power unit swinging freely across the top of the compartmentduring the rotation of the rotatable mast.

5. The combination with a vehicle, of a crane normally supported by thevehicle, and a caster wheel for providing an auxiliary support for thecrane, said caster wheel being mounted on a member, and guide means forpermitting either end of the member to swing laterally when the casterwheel swings about a vertical axis, the swinging of the member dependingon the direction of movement of the vehicle.

6. The combination with a vehicle, of a crane carried thereby, saidvehicle being strong enough to support the crane when the latter doesnot carry a load, a caster wheel carried by the vehicle and designed tocontact the ground for aiding the vehicle in supporting the crane whenthe latter carries a load, and spring means interposed between thecaster wheel and the vehicle for proportioning the load of the cranebetween the vehicle and the caster Wheel.

GROVER A. McCLAIN.

